Electric Actuated Swashplateless rotor head with non slip ring electric power supply

While individual blade control has been studied for over 30 years, it has yet to be implemented on production aircraft due to the uncertainties that the power transmission system to the IBC actuators can be as reliable as a mechanical linkage via a swashplate. Pochari Technologies has successfully solved this concern by using a non slip ring power system. While others have investigated IBC systems, Pochari Technologies aims to be the first rotorcraft manufacturer to integrate this new technology on production aircraft. Pochari Technologies’s founder Christophe Pochari first began conceptualizing electrically actuated rotor heads in 2017.

Slip rings are not required to achieve electric IBC. Pochari Technologies has solved the long-standing issue facing IBC which was the need for either hydraulic slip rings or electric slip rings. A simple solution is where a permanent magnet generator is mounted on the rotating assembly, a shaft passes through the drive system to the fixed assembly, providing constant power as long as the rotor system is spinning. The system provides a comparable if not higher level of redundancy than traditional swashplate-pitch link hydraulic rotor control systems while eliminating all their disadvantages. IBC provides up to an 80% reduction in vibration and significant reduction in acoustic signature, 5 db or more. Reduced power consumption, in the order of 5-7% is also attainable. IBC also increases rotorcraft agility and maneuverability.

“The electric actuators are powered by a shaft-mounted power generation system. In such embodiments, the stator of the generator may be mounted to the stationary part of the mechanical transmission and the rotor of the generator to the shaft. Thus, power generation is made integral to the rotor shaft, reducing the complexity of transmitting power through the rotating interface. In the event main turbine or auxiliary power is lost, power will be generated for control actuation as long as the rotor is rotating. Thus, control is provided during autorotation in the event of an unpowered landing. In other embodiments, the electric actuators draw power from power lines run up a hollow rotor shaft that transmit electric power by means of brushes or brushless slip rings or similar non-mechanically-linked electrical connections at the bottom or lower part of the rotor shaft.”

“To achieve swashplateless primary flight control in helicopters, on-blade control is required both to provide cyclic control for maneuvering and to ameliorate high levels of vibration and noise. High levels of vibration in rotorcraft cause various problems, including structural fatigue, pilot fatigue, reduced rotorcraft readiness, and increased costs of development and maintenance. Current helicopters typically employ passive vibration isolation and absorption to reduce fuselage vibration. However, these passive devices are heavy and have various other limitations. Past attempts to further reduce vibration have used active techniques such as higher harmonic control of the swashplate and individual blade control by means of active pitch links at the root of each blade”.

“Rotorcraft such as helicopters commonly make use of a complex mechanical device known as a “swashplate” to control collective pitch (for providing a change in altitude) and cyclic pitch (for providing change in attitude, and thus maneuvering). By actuating the angles of attack of the rotor blades, each of which is capable of rotating at its root, where it connects to the rotor head, the collective and cyclic pitch of the helicopter can be controlled”

The swashplate, which comprises a non-rotating lower plate movably connected to a rotating upper plate by bearings, is typically located just below the rotor head on the axis of the main rotor shaft, and is itself typically actuated by hydraulic cylinders mounted to the chassis. When rotorcraft controls actuate the hydraulic cylinders, the hydraulic cylinders move and pitch the non-rotating lower plate up and down and at an angle with respect to the plane of the main rotor. This up-and-down movement and/or pitch is transferred to the rotating half of the swashplate. The rotating half of the swashplate thereby transmits the motion of the stationary actuators to the several rotating pitch links, which connect the upper plate of the swashplate to the blade roots and act as lever arms, increasing or decreasing the blades’ angle of attack.

A swashplate, however, disadvantageously adds weight and aerodynamic drag to a rotorcraft, which can in turn reduce power, speed, maneuverability, and increase cost of flight. Another major disadvantage of a swashplate is that it limits control inputs to one per revolution of the rotor blades (except in the case of a three-bladed rotor). In addition, because of its mechanical complexity and the fact that it provides a single point of critical failure, swashplates necessitate many hours of inspection and preventative maintenance. The pitch links of a swashplate, which occupy a relatively large volume on the upper side of a rotor shaft and are therefore difficult to shield, also introduce significant ballistic vulnerability, as from missile attack, flak, and other flying debris. Damage to any one of the pitch links results in a loss of rotorcraft control.

3 thoughts on “Electric Actuated Swashplateless rotor head with non slip ring electric power supply

  1. Hello Mr. Pochari,

    I’m a 3rd-year Aerospace Engineering student at San Jose State University, about two hours from where you’re located in Bodega Bay. My concentration is in groundbreaking forms of propulsion for eVTOL technology. You seem like a fascinatingly smart individual, with a lot of very interesting concepts in the realm of rotary-wing propulsion, multiple of which that you have posted seem highly valuable for usage in overcoming traditional challenges associated with all-electric flight vehicles. Would you mind reaching out to me via my personal email to talk further?

    -Best wishes,
    Austin Coleman

  2. There may be a patent on this already – see the 2012 US PN 8,197,205 for some details. (uspto.gov)

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